The Ontario government has announced that the last refurbished reactor at the Darlington Nuclear Generating Station in Clarington, Ontario, will restart operations four months earlier than anticipated. This development marks the conclusion of a significant multibillion-dollar refurbishment programme designed to extend the facility’s operational life for another thirty years.
Accelerated Completion of Unit 4
The refurbishment work on Unit 4 reached completion on January 19, with initial power testing slated to commence later this month. Remarkably, the overall project cost came in at $150 million less than the original budget of $12.8 billion. The early return to service of Unit 1, which was overhauled prior to Unit 4, also highlights the effectiveness of this refurbishment strategy, as it resumed operations five months ahead of schedule.
Ontario Power Generation (OPG) is being lauded for its performance, with Ontario officials expressing confidence in the utility’s capabilities. Energy Minister Stephen Lecce stated, “OPG is emerging as the most credible nuclear operator and builder on Earth. We’re the only ones building on time, and we’re building on budget.” Minister Lecce emphasised that Unit 4 represents an opportunity to further demonstrate OPG’s reliability in the nuclear sector.
Challenges Ahead
However, despite this positive news, OPG faces additional challenges that may require substantial investment. In a recent rate application, the utility revealed that turbine rotors need replacing, a task that is expected to cost around $2 billion. OPG explained that this necessity arose from in-depth inspections conducted during the refurbishment programme, which uncovered issues with components that are not typically examined during standard maintenance.
Further maintenance concerns have also emerged. The stators on the generators of Units 1 and 2 require rewinding, an expense projected at $300 million. Additionally, there are plans to replace primary moisture separators in the steam generators for $235 million and upgrade the turbine control and auxiliary systems on Unit 2 at an estimated cost of $115 million. These financial commitments come despite earlier assurances from OPG in 2018 that the steam generators were in “excellent condition” for continued service.
A History of Nuclear Challenges
Constructed during the 1980s and 1990s, the Darlington facility has consistently produced approximately one-fifth of Ontario’s electricity. The CANDU reactors were initially designed for a 30-year lifespan, and following a decade of planning, refurbishment efforts commenced in October 2016. Although refurbishing a mid-life reactor is less daunting than constructing a new facility, it remains a complex task. This process necessitates the removal of nuclear fuel and the replacement of several hundred pressure tubes, which are essential to reactor function.
OPG’s previous experiences with refurbishments, particularly at the older Pickering Nuclear Generating Station, have provided valuable lessons. The failures at Pickering, particularly the delays and budget overruns, have informed OPG’s approach at Darlington and contributed to its current success. Critically, a 2010 report by the Ontario Clean Air Alliance had predicted potential costs for the Darlington project could reach as high as $35 billion based on historical overruns but has since proven to be far more manageable.
Future Developments
The refurbishment of the Darlington station is expected to extend its operational lifespan until at least 2055. Meanwhile, Bruce Power is undertaking its own refurbishment of six units at its facility in Kincardine, Ontario, with similar reports indicating that this project is also on track and on budget. The Ontario government has recently authorised OPG to refurbish four newer reactors at Pickering, with a projected budget of $26.8 billion—greater in nominal terms than the combined costs of the Darlington and Bruce refurbishments.
Why it Matters
The successful completion of the Darlington refurbishment programme is a significant milestone for Ontario’s energy sector, demonstrating that large-scale nuclear projects can be executed effectively. This achievement not only enhances the reliability of Ontario’s power supply but also boosts confidence in future nuclear initiatives. As the world grapples with energy sustainability and climate change, OPG’s achievements may serve as a model for other jurisdictions contemplating similar developments, reinforcing the viability of nuclear energy in the pursuit of a low-carbon future.
